Performance of the AquaCrop model for corn hybrids under different irrigation strategies¹

Desempenho do modelo Aquacrop para híbridos de milho sob diferentes estratégias de irrigação

HIGHLIGHTS:

The AquaCrop model is efficient in estimating corn crop yield.

Crop data used in the model calibration fits different corn hybrids, demonstrating the robustness of the model.

Decisions based on irrigation strategies can be made by using the AquaCrop model.

ABSTRACT

The objective of this study was to evaluate the performance of the AquaCrop model in the estimation of grain yield and crop water yield for nine hybrids of corn with different irrigation strategies in the municipalities of Santiago, Chile, and Alegrete, in the western region of the state of Rio Grande do Sul, Brazil. Data on climate, soil, management and crop yield over four crop seasons (2015 to 2019) were used, the first two in Santiago city, and the third and fourth in Alegrete city. The experimental design was randomised blocks, consisting of five irrigation treatments (0, 50, 75, 100 and 125% of crop evapotranspiration), and four, six and one hybrid, respectively, for the first, second and third growing season. In the fourth crop season, one hybrid was considered and the treatments consisted of suppression in water supply to the crop during its reproductive period, corresponding to ETc during vegetative (ETc_Veg.) and reproductive (ETc_Rep.) phases, as follows: 0, 50_Veg./25_Rep., 75_Veg./37.5_Rep., 100_Veg./50_Rep. and 100% of ETc. The performance of the model, evaluated through statistical indicators, was “excellent” and “good” for the simulation of grain yield and crop water productivity, respectively. There was a tendency of the model to overestimate the results under conditions of water deficit, this being more pronounced under severe deficit than under mild deficit, or in the reproductive period of the crop, and a tendency to underestimate the results under conditions of irrigation without deficit, i.e., 100 or 125% ETc.

Key words:
Zea mays L.; modelling; water management; water deficit; corn hybrids